A steering unit for a small watercraft is known wherein a steering shaft (41) is rotatably supported with respect to a watercraft body (11) by a cylindrical bearing section (57) in which the steering shaft (41) is inserted. See, for example, JP-A No. 2003-137173.
The small watercraft is often used on the sea, so that the steering shaft (41) and the bearing section (57) are formed of synthetic resin from the viewpoint of anticorrosion.
Moreover, collars (57a, 57b) are provided interposedly between the steering shaft (41) and the bearing section (57) at an upper and lower portion of the bearing section (57).
Although the JP-A No. 2003-137173 does not describe the material of the collars (57a, 57b), it is desirable from the viewpoint of anticorrosion that the collars are formed of synthetic resin.
Moreover, the steering shaft (41) and the bearing section (57) are made of synthetic resin and their dimensional precisions are not always high, so that in order to prevent jolting of the steering shaft relative to the bearing, it is desirable that the collars are made from elastic materials such as rubber or the like for absorbs the jolting.
However, if a collar is formed from elastic materials, the following problems occur with respect to the steering unit for the small watercraft.
If the thicknesses of the collars formed from the elastic materials are made thick in order to positively prevent the jolting of the steering shaft relative to the bearing section, the steering shaft becomes a condition in which it is pushed by substantially the entire inner surfaces of the collars, so that rotation of the steering shaft becomes slow. Moreover, the inserting operation for pushing the steering shaft and the collars into the bearing section becomes very difficult.
Conversely, if the thicknesses of the collars are made rather thin in order that the steering shaft can be smoothly rotated and the inserting operation of the steering shaft and the collars into the bearing section can be easily performed, a problem occurs wherein the jolting of the steering shaft relative to the bearing section is easy to occur.